Air Disc Brake Production, Use & Performance:

Transcription

1 Air Disc Brake Production, Use & Performance: Gary Ganaway, ArvinMeritor Tel: FAX:

2 Air Disc Brake Production & Usage

3 Air Disc Brake History 1981: First North American Air Disc Brake Released June 1988: Air Disc Brake Standard Equipment on European Renault R420 4 x 2 High Cab-Over Tractor 1990: First All Wheel Air Brakes on Mercedes Benz 0404 Coach 1994: First North American All Wheel ADB Standard Equipment on MCI Renaissance Long Distance Coach 2001: Over 1.5 Million Air Disc Brakes Produced in Europe Over 200,000 Air Disc Brakes Sold in U.S.

4 Current Customer Base Fire & Emergency Rescue Spartan Motors Sutphen E1 Motor Homes Foretravel Monaco Coach Intercity Coach MCI Prevost Pierce FWD/Seagrave Used Extensively on Specialty Vehicles Where Duty Cycles Warrant Air Disc Brakes

5 European Drum to Air Disc Migration % of Air Braked Vehicles 100% 80% 60% 40% 20% 0% 1997 Air Drum Brakes Air Disc Brakes 76% 69% 61% 48% 28% 10% 13% Production Year

6 Why Air Disc Brakes in Europe? Cost Lower cost than IN-HOUSE drum brakes Cost of Ownership Faster servicing, less unscheduled stops Improved Stability High front axle loadings compared with N.A. Improved Braking Performance Shorter Stopping Distances Electronic Braking Systems Improved stopping distance and compatibility with sensing systems.

7 Market Differences Europe Have Outsourced ADBs to Replace Their Heavy, Expensive Drum Brakes Disc Brakes Cost Comparable to Drum Brakes Spec ing is Non-Existent Have Made Air Disc Brakes Standard North America Evolving Standard in Niche Applications Currently Buy Cam Brakes at About One-Half the Cost of Air Disc Brakes

8 400 Heavy Truck Retardation Capability Typical U.S. 5 Axle Tractor / Trailer Combination at 50 mph on 3.5% Downhill Grade GCW GCW Brakes Horsepower Today Time Period Rolling Resistance Aerodynamics Driveline Engine Braking

9 NHTSA / DOT Initiatives Objective: Cut heavy truck related fatalities in half by 2010 Reduce Heavy Truck Stopping Distance Requirement by 30% Already Demonstrated by Many Trucks Increased Front Brake Torque ECBS (as an Enabler) Coordinated Effort with the Heavy Truck Industry NHTSA 9-Step Program Evaluate Maintenance & Reliability History through the Intelligent Vehicle Initiative

10 Drum Brake Improvements There Have Been Many Improvements to Foundation Drum Brakes Extended Maintenance Better Automatic Adjustment New Lining Formulations for Better Life Disc Brakes Still Provide the Best Retardation Performance

11 Air Disc Brake Technological Attributes & Performance

12 Temperature and Fade Drum Brakes Torque Drum Temp Temperature Drum Torque N of stops

13 Temperature and Fade Drum vs Disc Disc Temp T Torque Drum Temp Disc Torque Temperature Drum Torque N of stops

14 Stability Brake Pull is Caused by Uneven Braking Torques Developed Between LH and RH Brakes Drum Brakes Have Built-in Mechanical Advantage (Brake Factor) Due to Self Energization of the Leading Shoe(s) Unequal Torque Is the Result of Variation in the Self Energization As a Result of Friction Level Variation Due to Fade Problem is Proportional to Brake Factor

15 Brake Factor vs. Friction 9.0 C* Brake Factor 20% 14% 6% Duplex Wedge Simplex Wedge S Cam Brake Disc Brake % Coefficient of Friction

16 Stopping Distance Comparison Trucks vs. Passenger Cars 141 Ft. Gap 194 Ft. 335 Ft NHTSA Working with Industry to Reduce Gap

17 Tractor Stopping Distances Disc vs. Current Drum Brake 700 Best Effort Stop (Feet) FMVSS 121 HD Tractor (355 ft) MPH Loaded 75 MPH Loaded All Drum Tractor All Disc Tractor Front Disc/Rear Drum Tractor

18 Tractor Stopping Distances Disc vs. Current Drum Brake 700 Best Effort Stop (Feet) FMVSS 121 HD Tractor (355 ft) Pass Car (194 ft) MPH Loaded 75 MPH Loaded All Drum Tractor All Disc Tractor Front Disc/Rear Drum Tractor EBS / Disc Tractor & Trailer

19 Production, Use & Performance Summary European Standard Niche U.S. Applications Improved Stability & Fade-Resistance Shorter Stopping Distances Superior Stopping Capability at Higher Vehicle Speeds NHTSA / DOT Currently Evaluating